Method for controlling a yaw system of a wind turbine

A method for operating a yaw system of a wind turbine, the wind turbine including a tower and a nacelle that rotates relative to the tower, the yaw system including a yaw bearing, an annular gear, and a plurality of yaw drives that include a motor with a motor brake, a gearbox, and a pinion operatively connected with the motor, the method comprising:

• operating the plurality of yaw drives to rotate the nacelle with respect to the tower;
• stopping rotation of the nacelle with respect to the tower to include closing the motor brakes of the yaw drives;
• after a predefined waiting time with the motor brakes closed, balancing loads experienced by the plurality of yaw drives of the yaw system by:
• reducing a braking friction applied by the motor brakes by opening the motor brakes for a predefined opening time and subsequently closing the motor brakes after the opening time;
• wherein the opening time has a minimum time value of 0.02 seconds based on a reaction time and wear characteristics of the motor brakes, and a maximum time value of 1.0 seconds based on one or more operating conditions of the wind turbine including yaw moment, nacelle inertia, nacelle rotational speed, and environmental conditions.